The development of both structural and functional neuroimaging has progressed significantly in the last decade. However, clinical application of functional neuroimaging techniques in epilepsy has been complicated by their unsatisfactory temporal and spatial resolution. Optical imaging of intrinsic signals (OIS) is a functional neuroimaging technique that measures cortical reflectance changes with millisecond temporal resolution and micron spatial resolution. These optical images are correlated with neuronal activity and are due to changes in cerebral blood volume, light scattering, and in hemoglobin and cytochrome oxidation state. In the preliminary studies, OIS was recorded from the somatosensory cortex of rats at, near infrared frequency (850 nm). OIS was shown to correlate well with seizure activities, in a recoverable and reproducible fashion. It was also noted that OIS changes could precede the initial EEG spikes for up to I minute. The goal of this project is to correlate multiplewavelength optical signals with both electrophysiological and immunohistochemical markers, and to establish a primary foundation of interpreting OIS seizure data. The results of this project can be applied in the future in various epilepsy models, such as in a cortical kindling model for the study of neuronal network behaviors during kindling process. OIS imaging might hold a promising potential of better understanding of epileptogenesis, seizure induction, cessation and propagation pathways. Additional application of OIS imaging during epilepsy surgery in defining the eloquent cortex and confirming the seizure focus should be explored thoroughly in the future. The candidate, Dr. Chen, is a neurologist and a cellular electrophysiologist who has the expertise of using patch clamp technique. His career goal is to elucidate the basic mechanisms of epilepsy by integrating all the research skills that he has learned or will learn in electrophysiology, optical imaging, neurochemistry and computer simulation. This project will be conducted at the UCLA School of Medicine under Drs. Toga and Wasterlain's guidance. Both mentors are internationally known authorities in their respective fields of research.